Combined steam and gas turbine and method of operating the same



H` HOLZWRTH Jan. 12, 19.32.`

COMBINED STEAM AND GAS TURBINE AND METEQD" OF OPERATING THE SAME Filed Jan. 29. 1927 2 sheets-sheet NS, Q

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COMBINED STEAM AND GAS TURBINE AND METHOD OF OPERATING THE SAME A TTOR/V E KS Patented Jan. 12, 1932 UNITED STATES PATENT OFFICE HANS HOLZWARTH, OF DUSSELDORF, GERI'IANYLASSIGNOR TO HOLZWABTE GAS TUR- BINE C0., 0F SAN FRANCISCO, CALIFORNIA, A CORPORATION OF DELAWARE COMBINED STEAM AND GAS TURBINE AND METHOD OPERATING THE SAME Application led January 29,

In the operation of turbines the driving medium of which consists of combustion gases, considerable diiiiculties have been encountered hitherto on account of the metals employed so far for turbine blades being unable to withstand the high temperatures of said gases. For this reason, resort has been had to cooling arrangements, and one of the expedients adopted for keeping the metal of the blades, and particularly the rotor blades, from exceeding a maximum temperature of about 400 or 450 centigrade, has been the passage of air or steam in contact with such blades so as to absorb some of the heat of the combustion gases. Recently, however, turbine blades have been made of metals which even at temperatures as high as 650 exhibit a sufficient strength, in fact a greater strength than the air-cooled or. steam-cooled blades referred to above. Blades made of such heatresisting metals or alloys may therefore be exposed to the high-temperature combustion gases Without requiring any cooling by air or steam. This enables me to conduct the combustion gases from the combustion chamber to a rotor driven exclusively by such gases, the exhaust combustion gases being then conveyed to a turbine operating at a lower pressure, and driven both by said gases and by the steam exhausting from a steam turbine. The gases and the Steam exhausting from this second turbine may be utilized in various Ways.

rIwo examples of turbine plants embodying my present invention are illustrated by Figs. 1 and 2 of the accompanying drawings, each of said views being a diagrammatic longitudinal section.

In each of the constructions shown, l0 designatesl the rotor of the combustion gas turbine, driven exclusively by combustion` gases issuing from nozzles 11 which, when the valves 12 are open, receive such gases from chambers such as 13 provided with spark plugs or other ignition devices (not shown) and also having valves, as indicated at 14. 15 and 16 for the admission of fuel. c0m,

bustion air, and scavenging air respectively. The ignition devices andthe several valves are controlled by su1table means from the rotor 1927. Serial No. 164,407.

shaft 17 or some other moving part of the machine, in a manner readily understood by anybody skilled in this art. The gases which have exerted their driving action on the rotor 10 are collected in a chamber 18 and leave the latter through an outlet 19. It will be understood that the blades of the rotor 10 are made of a metal or alloy which will preserve the requisite strength at the temperatures to which said blades are subjected by the gases issuing from the nozzles 11, and that such metal or alloy will render it unnecessary to cool the said blades by air or steam as was found necessary khitherto in order to secure satisfactory results in practice. As an example ofxa metal or alloy suitable for the blades 10, I will mention one composed of nickel, 15% 'cromium, 15% iron, 7 molybdenum and the balance carbon, phosphorus, manganese, sulphur and silicon.

At 20, I have indicated a steam turbine of any suitable construction. The shaft 17 of the gas turbine is illustrated as constitutingv at the same time the shaft of the steam turbine, but I do not wish to restrict myself to this specific construction. The two turbines and their parts are so proportioned that the exhaustsof both will have substantially the same pressure when they reach the combined gas and steam turbine 2l. The latter has gas nozzles or stator blades 22 to direct the exhaust gases against the rotor blades 23, and also steam nozzles 24 to project the exhaust steam against said blades 23, at other points of the periphery of the rotor. The turbine 21 is preferably made with a plurality of sets of rotor blades and stator blades, increasing in area from the inlet toward the outlet, corresponding to the expansion of the gases and steam. The gases leave this turbine through an outlet 25, while the steam is received by separate catch nozzles 26. The latter are connected with the inlet chamber 27 of a turbine 28, driven exclusively by steam, preferably a condensing turbine. At 29 I have indicated the condenser connected with the outlet 30 of the turbine 28, the condensate passing through a pipe 31 to a pump 32 which forces it into the tubes or coils 33 in which steam is again generated from such water or condensate, the steam then passing through a pipe 34 to the inlet of the steam turbine 20. It will be understood that inthe combined gas and steam turbine 21, the steam not only serves to drive the turbine (in conjunction with the exhaust' combustion gases), but also acts as a cooling medium to keep this turbine from becoming too hot. At the same time, the steam itself becomes hotter, and is therefore utilized to better advantage in the steam turbine 28.

l prefer to derive the heat for the generation oi steam in the tubes 33, from the ex.- haust combustion gases. According to Fig. l, the said tubes are placed in a casing or heater (boiler) 35 connected with the gas outlet 25 of `the turbine 21, such gases passing out at 36 to the surrounding air or to any suitable place of use. In this. case, the outlet 19 of the gas turbine is connected directly with the inlet chamber 37 of the turbine 21.

According to Fig. 2, the outlet 19 of the explosion gas turbine 10 is connected with the interior of the casing 35', and from the outlet 36 of such casing the gases pass to the inlet chamber 37 of the turbine 21. In

vthis case, the gases leaving the turbine 21 through the gas outlet 25 either escape into the surrounding air or are'conveyed to any suitable place of use. Y

In both forms of my invention illustrated by the accompanying drawings, the rotors of all the turbines are mounted rigidly on the same shaft 17, but other arrangements might be adopted. Y

It will be understood that the construction and arrangement of the several parts may be varied in numerous ways without departing from the nature of my invention as defined in the appended claims.

claim:

1. A turbine power plant comprising acombustion gas turbine having blades made of a material capable of resisting a high temperature Without requiring any cooling, a steam turbine, and a combined gas and steam turbine receiving as its driving medium, the exhaust from both rst-mentioned turbines, at substantially the same pressure.

2. A turbine power vplant comprising a combustion gas turbine having blades made of a material capable of resisting a high temperature without requiring any cooling, a steam turbine, a combined gas and steam turbine having separate inlets for gas and steam respectively, and connections for leading the exhaust from the two first-mentioned turbines to the respective inlets of said combined turbine. A y

3. A turbine power plant comprising a combustion gas turbine having blades made of a material capable of resisting a high temperature without requiring any cooling, a steam turbine, a combined gas and steam turbine having separate inlets and separate outlets for gas and steam respectively, connections for leading the exhaust from the two first-mentioned turbines to the respective inlets of said combined turbine, and a steam turbine connected with the steam outlet yof said combined turbine.

t. A turbine power plant comprising a cornbustion gas turbine having blades made of a material capable of resisting a high temperature Without requiring any cooling, a steam turbine, and a combined gas and steam turbine receiving as its driving medium, the exhaust trom both irst-mentioned turbines, at substantially the same pressure, and a boiler, heated by the exhaust combustion gases, for supplying steam to said first-mentioned steam turbine.

5. A turbine power plant comprising a combustion gas turbine having blades made of a material capable of resisting a high temperature without requiring any cooling, a steam turbine, a combined gas and steam turbine having separate inlets and separa-te outlets for gas and steam respectively, connections for leading the exhaust from the two firstmentioned turbines to the respective inlets of said combined turbine, a steam turbine connected with the steam .outlet of said combined turbine, and a boiler, heated by the exhaust combustion gases, for supplying steam to said first-mentioned steam turbine.

6. A turbine power plant comprising a combustion gas turbine having blades made of a material capable of resisting a high temperature without requiring any cooling, a. steam turbine, a combined gas and steam turbine having separate inlets and separate outlet-s for gas and steam respectively, connections for leading the exhaust from the two first-mentioned turbines to the respective inlets of said combined turbine, a second steam turbine connected with the steam outlet of said combined turbine, a condenser connected With the outlet of said second steam turbine, a boiler, heated by the exhaust combustion gases, for. supplying steam to said first-mentioned steam turbine, and a connection for conveying the condensate from said condenser `to said boiler.

7 The method which comprises expanding high temperature, high pressure combustion gases in a gas turbine to an exhaust pressure above atmospheric, expanding high temperature, high pressure steam in a steam turbine to substantially the same exhaust pressure. and further expanding the exhaust gases and exhaust steam in a combined gas and steam turbine.

8. The method as set forth in claim 7 including the vfurther step of expanding the steam exhausting from the combined gas and team turbine in a low'preure steam tur- 9. The method as set forth in claim 7 including the further step of conducting the hot combustion gases exhausting from the combined gas and' steam turbine to a steam generator to generate said steam.

10. The method as set forth in'claim 7 including the further steps of further expanding the steam exhausting from the combined gas and steam turbine in a condensing low pressure steam turbine, and conducting the condensed steam to aboiler generating said high temperature, high ressure steam.

In testimony whereof, have hereunto set my hand. i

HANS HOLZWARTH. 

